How to Check a Used Car Engine Before Buying

A used engine can save you 50-70% over a new one — but only if it's actually in good condition. Here's what to check before you commit, whether you're buying through a vendor or inspecting one in person.

1. Check the oil

Pull the dipstick. Oil should be amber to dark brown and smooth between your fingers. Milky or frothy oil means coolant is mixing with oil — a sign of a blown head gasket or cracked block. Gritty, metallic-smelling oil suggests internal wear.

2. Look at the exhaust smoke

Start the engine cold and watch the exhaust. Thin white vapour on a cold morning is normal condensation and clears in seconds. Thick white smoke that persists means coolant is burning — a head gasket or cracked head issue. Blue smoke means the engine is burning oil, usually worn piston rings or valve seals. Black smoke points to a fuel mixture problem.

3. Listen for unusual noise

A knocking sound that gets faster with RPM usually means worn bearings — expensive to fix. A ticking noise could just be a loose heat shield or valve clearance, less serious. Any noise that changes character sharply is worth walking away from unless the seller drops the price to cover a proper mechanic inspection.

4. Check for leaks

Look underneath for oil or coolant stains. A little seepage around old gaskets is common and not a dealbreaker on a used engine — active dripping is. Ask the vendor how long the engine has been sitting; a fresh puddle after sitting overnight is more telling than smears from months ago.

5. Ask for the engine number and history

A genuine salvage vendor can tell you which vehicle the engine came from, roughly how many kilometres it ran, and why that vehicle was scrapped (accident vs. natural end-of-life vs. flood damage). Accident-origin engines are usually fine if the engine bay itself wasn't damaged — ask specifically.

Why Xspare's grading helps

Every part on Xspare is graded A, B or C by the vendor before you buy — Grade A is near-new condition, Grade B is good working condition with normal wear, Grade C is functional but with visible wear. Submit an enquiry with your vehicle details and you'll get quotes with the grade already specified, so you know what to inspect for before you agree to buy.